President Ronald Reagan famously said, “Latinos are Republicans — they just don’t know it yet.” With respect to the Gipper, we’d like to make a slight edit to his adage: “Some Latinos lean Republican — they just won’t vote for Republicans until the GOP moves away from its hardline immigration stance.”

While our addendum makes the adage less memorable, new polling data bears out the truth of our revision. Even among Latino Protestants, the most socially conservative and traditionally Republican subset of Latino voters, there has been a dramatic erosion of support for Republicans ever since the GOP moved away from the pro-immigration reform stance of George W. Bush and instead became associated with an anti-immigrant identity. Polling data released yesterday by the Pew Hispanic Center and the Pew Forum on Religion & Public Life found that Latino Protestants favor President Obama over Mitt Romney by a 55%-33% margin, including a 50%-39% margin among Latino evangelicals.

As Ron Brownstein of National Journalnoted this summer, George W. Bush “made his greatest gains among Hispanic Protestants, winning just under half of their votes in 2000 and a 54 percent majority in 2004. Protestants make up about one-fifth of all Hispanics, and evangelicals, preponderantly socially conservative, represent about two-thirds of that group.” Overall, Bush won over 40% of the Latino electorate in 2004, including majority support among Latino voters in the crucial swing state of Florida.

A major reason for Bush’s success among Latino voters was that he offered a pro-immigration reform message and set of policies, in contrast to the current hardline immigration approach touted by Romney. For socially conservative Latino voters, in contrast to Romney, Bush did not force them to be “torn between immigration and religious stances important to them,” to borrow the phrase of National Journal’s Rosa Ramirez. Indeed, the Pew data even found that immigration is tied to Latinos’ religious experiences – among Latino voters attending religious services at least monthly, 43% reported hearing their clergy speak out about immigration.

According to Frank Sharry, Executive Director of America’s Voice, “These new numbers are more evidence that the Republican Party’s immigration stance is the Democratic Party’s best tool for Latino voter recruitment. Beyond 2012, the GOP’s future viability in national elections will be threatened so long as the Party would rather appeal to the narrow contingent of anti-immigrant voters instead of the fastest growing demographic group of voters in the electorate.”